69 research outputs found

    Electrorefining of base metal refinery residue copper alloy for platinum group metal recovery

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    Secondary leach concentrate (SLC) is an important bleed stream for minor elements from Anglo Platinum’s Base Metal Refinery (BMR) which produces copper nickel and cobalt sulphate. It contains mainly sulphur, iron jarosites, unleached base metals and platinum group metals (PGMs), which makes the treatment of SLC necessary. The SLC is currently toll-refined at Umicore’s Hoboken smelter and refinery to recover revenue from entrapped valuable metals. This method of treatment results in excessively high costs due to high transport and toll refining expenses as well as penalties. Thus, an in-house method of treatment by Anglo Platinum itself would prove beneficial in that it would eliminate these excessive costs and also provide a method of treatment in the event of residues exporting becoming banned or strongly penalised in future. Therefore, a method for treating SLC in-house is investigated. The first stage of the proposed treatment method involves a pyrometallurgical process where the removal of amphoterics by oxidative fuming, followed by reduction to recover base metals from the slag takes place. The PGMs are reported mainly to the metal alloy phase along with the base metals during this process. The project discussed in this report deals with the treatment of this furnace alloy which is referred to as Cu alloy. The Cu alloy is used to produce anodes to be applied to an electrorefining application for the recovery of Cu as a Cu cathode and PGMs in the form of anode slimes. Spent electrolyte from the BMR copper electrowinning section adjusted to specific pH and Cu concentration is used as electrolyte to which dissolvable metals (such as Ni and Fe) are recovered

    Een continue functie met sterk transfiniete omkering

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    Over de congruentie u@ 1 modulo p

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    A combinatorial problem on finite abelian groups, 3

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    A combinatorial problem on finite abelian groups, 3

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    Baas in eigen boek?: Evolutietheorie en schriftgezag bij de Gereformeerde Kerken in Nederland (1881-1981)

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    In Baas in eigen Boek wordt de ontwikkeling geschetst die zich in de Gereformeerde Kerken in Nederland (GKN) tussen ongeveer 1880 en 1980 voltrok wat betreft hun visie op de darwinistische evolutietheorie en in het bijzonder de daaruit voortvloeiende wereldbeschouwing. De evolutietheorie bleek decennialang onverenigbaar met 'eenvoudighistorische' en vrijwel letterlijke lezing van het scheppingsverhaal in het eerste Bijbelboek Genesis die in de GKN gangbaar was. Kerkelijke gezagsdragers, theologen en natuur-onderzoekers voerden hier verhitte debatten over, zo laat Kruyswijk zien. De ontzuiling van de jaren zestig van de twintigste eeuw droeg ertoe bij dat gereformeerde natuuronderzoekers deze lezing van Genesis niet langer konden volhouden. Mede door hun toedoen namen de GKN in 1981 officieel een narratieve interpretatie van de Bijbelse geschiedschrijving aan. Principiële bezwaren tegen de evolutie-theorie waren daarmee weggenomen. Veel gereformeerden bleven niettemin aan het 'eenvoudig-historische' gezag van de Bijbel vasthouden.UBL - phd migration 201

    Underground mining of aggregates. Main report

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    This report examines the economic feasibility of underground mining for crushed rock aggregates in the UK, but particularly in the London, South East and East of England regions (the South East area of England). These regions import substantial volumes of crushed rock, primarily from the East Midlands and South West regions, requiring relatively long transport distances to market for this bulk commodity. A key part of the research was to determine whether or not aggregate could be produced and delivered to a local market from an underground aggregates operation at a cost comparable with that for production and transport of the commodity from traditional surface quarries located further afield. In essence the investigation asked – could the reduced transport costs compensate for the higher production costs underground so that underground crushed rock aggregates producers can compete with the established Leicestershire and Somerset surface quarries exporting to the South East? Work Programme The research effort involved establishing and verifying cost models for aggregates production, stone processing (sizing and sorting), haulage of product to market, environmental impact mitigation, health and safety, decommissioning and restoration. Another major element of the work was the re-examination of the BGS exploratory borehole and geophysical databases to identify potential areas of crushed rock aggregates resource at depth in the South East area of England. Land use pressure is typically higher in this area of England than elsewhere so another major part of the research was the identification of potential concurrent uses of land around the surface facilities of underground aggregates mines. The value, development costs for specific developments and determination of yields expected, from these uses were estimated. These were also used to investigate potential economic benefits associated with after uses of remediated surface land above potential underground aggregates mines and also for the new underground space that would be created. Key technical issues such as subsidence within relatively heavily populated areas of the South East area of England were also addressed. Economic Results The discounted cost of aggregate delivered at a discount rate of 10% was the metric used to appraise the options. This is the price of aggregate that leads to a zero net present value of project cash flows realised over the aggregates project life. The results show that the discounted costs of aggregate delivered to a local South East area of England market from an underground mine producing 3.5 million tonnes per annum (MTPA) of crushed rock aggregates, are in the range of £13.03 per tonne to £13.93 per tonne for the top six prospect locations. These are greater than the corresponding cost for a “reference” quarry in Leicestershire producing 3.5 MTPA (£10.95 per tonne), but lower than a “reference” quarry in Leicestershire producing 1.25 MTPA (£16.48 per tonne). These figures indicate that underground crushed rock aggregate mines located within the South East area of England may be able to compete for a share in the overall market by replacing / displacing aggregate imported from the quarries in Leicestershire and Somerset producing around or less than 1.25 MTPA. The surprise in these figures is not really that the more remote surface quarry has a lower discounted cost of aggregate delivered, but that the values for the quarry and underground mine are so close. The capital intensity for the development of underground aggregates mines was found to be higher than that required for surface quarries of comparable scale, by a factor ranging from 1.33 to 1.65 and thus may represent a disincentive for aggregates operators. Carbon Emissions The total carbon emissions of the ‘reference’ 3.5 MTPA quarry in Leicestershire were estimated at 9.28 kg CO2/tonne aggregate delivered and this is to be compared with carbon emissions for the 150 metre deep underground mines serving the local market which were estimated at 9.31 kg CO2/tonne delivered for a Bletchley prospect using an adit to access the sub-surface and 14.25 kg CO2/tonne delivered for a prospect based on the Chitty bore hole using a shaft. Depth of the mine is a key factor in determination of the relative carbon emissions from each of the underground mining operations considered as electricity consumption for ventilation, pumping and winding is proportional to depth. Recommendations The current research generated seven principal recommendations which are discussed in detail in the concluding section of the report. These are: Appraise policy incentives for underground aggregates mining. Conduct an industry-wide consultation on findings from the current research. Obtain public and stakeholder opinion on new uses for underground space. Conduct research to reducing the energy intensity of mine services. Develop a deep level aggregates-specific drilling campaign. Investigate underground aggregates mines developed from existing surface quarries. Investigate underground aggregates as co-products of industrial minerals mining

    Hypocapnia Alone Fails to Provoke Important Electrocardiogram Changes in Coronary Artery Diseased Patients

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    Background: There is still an urgent clinical need to develop non-invasive diagnostic tests for early ischemic heart disease because, once angina occurs, it is too late. Hypocapnia has long been known to cause coronary artery vasoconstriction. Some new cardiology tests are accompanied by the claim that they must have potential diagnostic value if hypocapnia enhances their cardiac effects in healthy subjects. But no previous study has tested whether hypocapnia produces bigger cardiac effects in patients with angina than in healthy subjects. Methods: Severe hypocapnia (a PetCO2 level of 20 mmHg) lasting >15 min was mechanically induced by facemask, while conscious and unmedicated, in 18 healthy subjects and in 10 patients with angina and angiographically confirmed coronary artery disease, awaiting by-pass surgery. Each participant was their own control in normocapnia (where CO2 was added to the inspirate) and the order of normocapnia and hypocapnia was randomized. Twelve lead electrocardiograms (ECG) were recorded and automated measurements were made on all ECG waveforms averaged over >120 beats. 2D echocardiography was also performed on healthy subjects. Results: In the 18 healthy subjects, we confirm that severe hypocapnia (a mean PetCO2 of 20 ± 0 mmHg, P 0.05) on their electro- or echocardiogram. All 10 angina patients tolerated the mechanical hyperventilation well, with minimal discomfort. Hypocpania caused a similar increase in V1 (by 39%, P 0.05 vs. healthy controls) and did not induce angina. Its effects were no greater in patients who did not take β-blockers, or did not take organic nitrates, or had the worst Canadian Cardiovascular Society scores. Conclusion: Non-invasive mechanical hyperventilation while awake and unmedicated is safe and acceptable, even to patients with angina. Using it to produce severe and prolonged hypocapnia alone does produce significant ECG changes in angina patients. But its potential diagnostic value for identifying patients with coronary stenosis requires further evaluation

    Teclistamab impairs humoral immunity in patients with heavily pretreated myeloma:importance of immunoglobulin supplementation

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    Teclistamab and other B-cell maturation antigen (BCMA)-targeting bispecific antibodies (BsAbs) have substantial activity in patients with heavily pretreated multiple myeloma (MM) but are associated with a high rate of infections. BCMA is also expressed on normal plasma cells and mature B cells, which are essential for the generation of a humoral immune response. The aim of this study was to improve the understanding of the impact of BCMA-targeting BsAbs on humoral immunity. The impact of teclistamab on polyclonal immunoglobulins and B cell counts was evaluated in patients with MM who received onceweekly teclistamab 1.5 mg/kg subcutaneously. Vaccination responses were assessed in a subset of patients. Teclistamabinduced rapid depletion of peripheral blood B cells in patients with MM and eliminated normal plasma cells in ex vivo assays. In addition, teclistamab reduced the levels of polyclonal immunoglobulins (immunoglobulin G [IgG], IgA, IgE, and IgM), without recovery over time while receiving teclistamab therapy. Furthermore, response to vaccines against Streptococcus pneumoniae, Haemophilus influenzae type B, and severe acute respiratory syndrome coronavirus 2 was severely impaired in patients treated with teclistamab compared with vaccination responses observed in patients with newly diagnosed MM or relapsed/refractory MM. Intravenous immunoglobulin (IVIG) use was associated with a significantly lower risk of serious infections among patients treated with teclistamab (cumulative incidence of infections at 6 months: 5.3% with IVIG vs 54.8% with observation only [P &lt; .001]). In conclusion, our data show severe defects in humoral immunity induced by teclistamab, the impact of which can be mitigated by the use of immunoglobulin supplementation. This trial was registered at www.ClinicalTrials.gov as #NCT04557098.</p
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